Magnetic domain fluctuations in an antiferromagnetic film observed with coherent resonant soft x-ray scattering

TL;DR

This study uses coherent resonant soft x-ray scattering to directly observe slow, non-ergodic fluctuations of antiferromagnetic domains in an ultrathin holmium film, revealing temperature-dependent domain-wall dynamics.

Contribution

It provides the first direct observation of slow antiferromagnetic domain fluctuations in a thin film using coherent resonant x-ray scattering, highlighting non-ergodic behavior.

Findings

Fluctuations increase with temperature

Presence of static speckle contributions

Domain-wall fluctuation rates depend on local thickness

Abstract

We report the direct observation of slow fluctuations of helical antiferromagnetic domains in an ultra-thin holmium film using coherent resonant magnetic x-ray scattering. We observe a gradual increase of the fluctuations in the speckle pattern with increasing temperature, while at the same time a static contribution to the speckle pattern remains. This finding indicates that domain-wall fluctuations occur over a large range of time scales. We ascribe this non-ergodic behavior to the strong dependence of the fluctuation rate on the local thickness of the film.